27 Fever Exhaust
 

Need some feedback from anyone who has tried different exhaust systems on a 27 fever with a 502 MAG MPi. I am considering the IMCO powerflows because they are easy to hook up to my stock silent choice and would like to know what kind of an performance improvement to expect. The sales people say 3-5 mph. Sounds to a bit optomistic to me. I have a vortech flame arrestor, msd. Going to get a reprogrammed ECU and adjustable fuel pressure reg. Would like to know if the exhaust mod is worth while before I get the ECU programmed for my current set up. Is there something better that will hook up to my silent choice?

Thanks

I changed to CMI headers with their diverter valves. It was expensive but worth it to me. I probably picked up 2 mph top end but the midrange is much stronger. If you give it the gas while on plane it will put you in the seat much stronger. Another thing I got with CMI is the peace of mind of not having to worry about reversion. The CMI diverters are water jacketed so the water does not enter the exhaust stream until after the diverters. Plus they look awsome!

The only draw back to the CMI diverters is that they are air operated. I solved this problem by modifying them to accept the Corsa electric soliniods. It worked great. I didnt have to install an air pump and lines and run new wires up to the helm. The air system is prone to leaks and is somewhat slow operating. Now I just flip the switch and they open or shut immediatly with a reassuring click.

Ill have to post some pics of the system.

Ron

RJ

Please do post some pics, that sounds like the same system I would like to install. I would like to use my Corsca system also. What model CMI headers did you use? Any idea on the weight savings, the stock manafolds look very heavy.

Thanks.

Pics of the exhaust system

another view

other side

again

pic of the bracket I made out of 1/8" aluminum flatbar with the Corsa solinoids that came off of the system that was originaly installed in the boat

bracket and Corsa solinoid again

View from top

The headers are CMI E-Tops with CMI Sound Choice diverters. I paid the extra couple hundred bucks or so to get the brackets for the ECM and shift bracket welded in the headers. I had to trim the oil filter mounting bracket about 1" to make the port header fit. I also had to relocate the drive oil reservoir to the transom.

Besides the bracket that hold the solinoids that I had to make I had to use the valve vanes or plates from inside the Corsa tips also. To my surprise the holes even lined up when I swapped them. The CMI vanes are smaller and completely round and when disconected from the air piston will fully rotate in the diverter. The Corsa solinoids need a stop to push against when closed. Corsa does this by using a vane in the diverter that is oval and will not rotate fully inside. I had to trim the Corsa vanes slightly with a angle grinder to get a perfect fit.

Ron

Orion27 fever, I just had the imco power flows installed on my boat yesterday. I havent had a chance to check it out yet and to see how they look. I will hopefully get a chance to run it this weekend and i will let you know how it does.

BobbyB,
What prop are you running now and what are your top speeds. Is the engine stock other than the Imco's? Will be interesting to see what it does with the new exhaust.

Nice air filter :D

Thought you might notice that Von.

Ron
:cool:

Orion27 fever, My engine in pretty much stock except for the imcos and a emi air brether. I am also running a lefthand 24p hydromotive. I didnt get a chance to run it this weekend to much rain here:mad:. My top speed on the gps is 67.5 with a full tank of gas and on other person on board.

I have Stainless Marine and fit and finish is excellent. They also produce deeper sound than stock and of course less weight. They come with all the right brackets and fittings to make a clean installation.